Vitamins Essential organic compounds required in small amounts

Vitamins -Essential organic compounds required in small amounts for normal metabolism and good health - not a source of energy Water soluble - C and Bs -must be replenished everyday -Difficult to overdose Fat soluble - A, D, E, K -does not need to be replenished everyday -can cause toxicity

Names and Roles Vitamins A B 1 B 2 B 3 B 5 B 6 B 7 B 9 B 12 C D E K retinol thiamine riboflavin niacin Pantothenic acid pyridoxine pyridoxamine pyridoxal Biotin Folic acid cobalamin ascorbic acid cholecalciferol tocopherols phytylmenaquinone multiprenylmenaquinone phototransduction carbohydrate metabolism redox, respiration redox tca, fa and cholesterol aa metabolism glycogenolysis gluconeogenesis, tca, fa, aa 1 C metabolism 1 C&H metabolism hydroxylation bone remodeling antioxidant coagulation bone remodeling

Deficiencies and Sources Vitamins A - night blindness B 1 - beri-beri B 2 - pellagra B 3 - pellagra B 5 - none known B 6 - neurologic disease preformed: liver, egg yolk, butter, milk b-carotene: dark green and yellow veggies seeds, nuts, wheatgerms, legumes, lean meats, nuts, legumes yeast, grains, egg yolk, liver yeast, liver, wheatgerm, nuts, beans, bananas B 7 - widespread injury corn, soy, egg yolk, liver, kidney, tomatoes B 9 - anemia B 12 - pernicious anemia yeast, liver, leafy veggies C - scurvy D - ricketts, osteomalacia E - neurologic? , hemolytic anemia K - bleeding disorders liver, kidney, egg, cheese citrus and soft fruits milk, fortified food, fish oils, egg yolks, liver veggie oils, nuts green leafy veggies, fruits, dairy products, veggie oils, cereals, meats

Recommended Daily Allowances (RDA)

Vitamin Absorption and Storage • All absorption takes place in the small intestine • Fat-soluble vitamins – Are absorbed in the duodenum – Storage • • Vitamin A is mainly stored in the liver Vitamins K and E are partially stored in the liver Vitamin D is mainly stored in the fat and muscle tissue Can build up in body to point of toxicity

Vitamin Absorption and Storage • Water-soluble vitamins – Absorbed with water and enter directly into the blood stream – Most absorbed in the duodenum and jejunum – Most are not stored in the body – Excess intake excreted through the urine – Important to consume adequate amounts daily – Dietary excesses can be harmful

Digesting and Absorbing Water-Soluble Vitamins Figure 10. 1

Water-Soluble Vitamins Small Intestine Fat-Soluble Vitamins Small Intestine Hydrophilic Hydrophobic Absorbed into the Blood Lymph Stored in the body Not Generally Yes Can build up and become toxic Not Generally Yes Need to consume daily Yes No Absorbed in the Hydrophobic or Hydrophilic

Bioavailability • Varies based on – Amount in food – Preparation – Efficiency of digestion and absorption of food – Individual nutritional status – Natural or synthetic • Fat-soluble vitamins are generally less bioavailable than water-soluble vitamins • Vitamins from animal foods are generally more bioavailable than those in plant foods

Fat Soluble Vitamins - Many have precursors Less vulnerable to cooking losses Can cause toxicity Transported like fat in chylomicrons, VLDL, LDL

vitamin A • • • aka: retinol Converted to active form Regulates response of rod and cone cells in the retina to light Regulates gene expression of development of epithelial tissue Used to treat severe acne, wrinkled skin 16

vitamin D • A prohormone synthesized from cholesterol • Vitamin D 3 = cholecalciferol • Found in animal products • Vitamin D 2 = egocalciferol • Found in plants and fortified foods 24

Vitamin D 3 and D 2

What affects your vitamin D level? • Time spent outdoors • Amount of skin exposed • Skin color • Clothing • Body fat • Latitude • Season and time of day

Vitamin D Synthesis and Latitude

Childhood rickets • Epidemic with industrialization in 19 -20 th centuries • With discovery of vitamin D and fortification, rickets was almost entirely eliminated • Until now…

London 1889 Idaho 1989

• • • 40 -90% of US community dwelling elderly 50% of premenopausal women 50% of Hispanic and black adolescents 48% of French preteens 30 -50 % of adults in Saudi Arabia and UAE 73 % of pregnant women taking prenatal vitamins …are DEFICIENT

How to get vitamin D. . . • 100 IU/d raises level by about 1 ng/m. L • Sunlight • Oily fish 3000 IU/10 minutes 300 IU/3 oz – Salmon, sardines, mackerel, tuna • Mushrooms 100 IU/3 oz • Fortified drinks 100 IU/8 oz – Milk, orange juice, yogurt, cereals

Endocrine, paracrine and intracrine functions of Vitamin D

• Role in Cancer Prevention – Low intake of vitamin D and calcium has been associated with an increased risk of non-Hodgkin lymphomas, colon, ovarian, breast, prostate, and other cancers. – The anti-cancer activity of vitamin D is thought to result from its role as a nuclear transcription factor that regulates cell growth, differentiation, apoptosis and a wide range of cellular mechanisms central to the development of cancer. These effects may be mediated through vitamin D receptors expressed in cancer cells. – Vitamin D is not currently recommended for reducing cancer risk

• Role in Cardiovascular Diseases – Vitamin D deficiency activates the reninangiotensin-aldosterone system and can predispose to hypertension and left ventricular hypertrophy. – Additionally, vitamin D deficiency causes an increase in parathyroid hormone, which increases insulin resistance secondary to down regulation of insulin receptors and is associated with diabetes, hypertension, inflammation, and increased cardiovascular risk.

Updated Recommendations In Process • Studies suggest that the daily vitamin D intakes should be much higher than 400 IU/d. • Daily intakes in the range of 800 to 1000 IU/d should be strongly considered. • Although there are concerns regarding vitamin D toxicity, side effects at intakes exceeding the current upper limit of 2000 IU/d have not been reported to date. • Assessment of vitamin D status with serum measurements of 25(OH) vitamin D levels for a broader range of patients should be encouraged.

Key clinical recommendation • Daily vitamin D supplementation of 800 to 1, 000 IU is a reasonable dose for adults. Levels of 25 -OH vitamin D should be maintained > 32 ng per m. L (80 nmol per L) to maximize bone health. • In patients with severe vitamin D deficiency, 50, 000 IU of vitamin D should be given daily for one to three weeks, followed by weekly doses of 50, 000 IU.

Vitamin E • There are four different tocopherol compounds, but only the alpha-tocopherol has vitamin E activity in human beings. • Vitamin E as an Antioxidant – Stops the chain reaction of free radicals – Protection of polyunsaturated fatty acids and vitamin A – Protects the oxidation of LDLs

Vitamin E • Easily destroyed by heat and oxygen • Deficiency symptoms – Red blood cell breakage – Nerve damage • Toxicity symptoms – Augments the effects of anticlotting medication

Vitamin E Deficiency – Primary deficiency due to inadequate intake is rare – Erythrocyte hemolysis • Occurs in premature infants • Hemolytic anemia can be treated with vitamin E.

Vitamin E Toxicity – Rare and the least toxic of the fat-soluble vitamins – Upper level for adults: 1000 mg/day – May augment the effects of anticlotting medication

Vitamin E • Other name: alpha-tocopherol • 2000 RDA – Adults: 15 mg/day • Upper level for adults: 1000 mg/day • Chief function in the body – Antioxidant (stabilization of cell membranes, regulation of oxidation reactions, protection of polyunsaturated fatty acids and vitamin A)

Antioxidant Nutrients In Disease Prevention

Vitamin E • Significant sources – Polyunsaturated plant oils (margarine, salad dressings, shortenings) – Leafy green vegetables, wheat germ, whole grains, liver, egg yolks, nuts, seeds

Vitamin K • Also known as phylloquinone, menadione, and naphthoquinone • Vitamin K is unique in that half of human needs are met through the action of intestinal bacteria. • Vitamin K is essential in blood clotting. • deficiency can cause uncontrolled bleeding. • Deficiencies can occur in newborn infants and people taking antibiotics.

Vitamin K • Vitamin K Deficiency – Symptoms include hemorrhaging – Secondary deficiencies may occur with use of antibiotics. – Newborn infants receive a single dose of vitamin K at birth because of a sterile intestinal tract.

Vitamin K • Other names – Phylloquinone – Menadione – Naphthoquinone • 2001 AI – Men: 120 g/day – Women: 90 g/day

vitamin K – Blood clotting cofactor – Prothrombin formation is blocked by warfarin – Deficiency is rare 51

Vitamin K • Chief functions in the body – Synthesis of blood-clotting proteins and bone proteins that regulate blood calcium

Vitamin K • Significant sources – Bacterial synthesis in the digestive tract – Liver – Leafy green vegetables, cabbage-type vegetables – Milk

Vitamin K • Deficiency symptoms – Hemorrhaging • Toxicity symptoms – None known